Multi-disk clutch

ABSTRACT

A multi-plate clutch, in particular a dual-plate clutch, for coupling a drivetrain of a motor vehicle engine having at least one transmission input shaft, in particular for a dual clutch is provided, having a counter plate for introducing a torque from the driveshaft, a clutch plate for channeling the torque to the transmission input shaft, the clutch plate having a first lining ring for frictionally engaged torque transfer and a second lining ring which is movable axially relative to the first lining ring for frictionally engaged torque transfer, a separator plate which is movable axially relative to the counter plate, the separator plate being positioned between the first lining ring and the second lining ring in the axial direction, and a contact plate which is movable axially relative to the counter plate by an actuating element to frictionally compress the clutch plate, the first lining ring being positioned between the contact plate and the separator plate in the axial direction and the second lining ring being positioned between the separator plate and the counter plate, there being n separator plates and n+1 lining rings provided, the movement of the separator plate in the axial direction being coupled with the movement of the contact plate in the axial direction by means of a coupling mechanism, where over at least part of the distance between an open position of the contact plate corresponding to the disengaged position of the multi-plate clutch and a maximum closed position of the contact plate corresponding to the engaged position of the multi-plate clutch when the lining rings are worn, a current distance translation ratio i(s A ) of the axial displacement of the contact plate to the axial displacement of the separator plate which is furthest distant in the axial direction from the contact plate at an axial position s A  of the contact plate deviates from i(s A )=n+1, and/or a current distance translation ratio i(s A ) j  of the axial displacement of the contact plate to the axial displacement of a jth separator plate at an axial position s A  of the contact plate deviates from i(s A ) j =(n+1)/j where j is counted starting from the counter plate in the direction of the contact plate. Because the distance translation ratio of the coupling mechanism deviates from n+1, the multi-plate clutch can easily be adapted to differently-dimensioned lining rings, so that transmission of an especially high torque is enabled with the help of a friction clutch with different configurations of a motor vehicle drivetrain.

The invention relates to a multi-plate clutch, in particular adual-plate clutch, with the help of which a driveshaft of a motorvehicle engine having at least one transmission input shaft can becoupled, the multiple-plate clutch being particularly well suited for adual clutch.

According to the present state of the art, in most cases dry dualclutches have one plate per sub-clutch. These plates have two frictionsurfaces each with which they are in contact with their neighboringcomponents (e.g., contact plate and central plate or counter plate) whenthey are clamped by the clutch to transfer torque, and thus they formtwo friction locations with the clutch. The torque transmissible by aclutch can be increased even with the same clamping force, same diameterand same friction conditions (coefficient of friction) by increasing thenumber of friction locations. This principle is frequently employed inlamellar clutches, such are used for example in wet-running dualclutches. As dry-running clutches, lamellar clutches are in most casesunsuitable for motor vehicle applications. Without oil, which cools theclutch, the thin plates overheat quickly, since they have too littleheat capacity. In addition, lamellar clutches do not clear properly inmost cases if the friction locations between the plates and the platecarriers are not lubricated by the oil. To be able to utilize thebenefits of multiple friction locations per clutch even with dry-runningclutches, there are by now inventions that show a way to integrate twoor more plates into a sub-clutch, and to realize this using parts andoperating principles that are proven for dry clutches.

From DE 10 2011 0185 589 A1 a dual-plate clutch is known in which acontact plate and a separator plate are each connected to a counterplate by means of a leaf spring. When the contact plate is moved axiallyrelative to the counter plate from a disengaged position of thedual-plate clutch into an engaged position of the dual-plate clutch,lining rings of a clutch plate provided between the counter plate andthe separator plate on one hand and between the separator plate and thecontact plate on the other hand are compressed. The separator plate issupported by means of a contact pin in the center of the extension ofthe leaf spring connected to the contact plate, so that the axial travelof the separator plate is always half as great as the travel of thecontact plate.

There is a constant need in the drivetrain of a motor vehicle to be ableto transmit an especially high torque with the help of a frictionclutch, with various constructions of the drivetrain.

The object of the invention is to point out measures that make itpossible to transmit an especially high torque with the help of afriction clutch, with various constructions of a drivetrain.

The object is fulfilled according to the invention by a multi-plateclutch having the features of claim 1. Preferred designs of theinvention are specified in the subordinate claims, which may eachportray an aspect of the invention, individually or in combination.

According to the invention, a multi-plate clutch, in particular adual-plate clutch, for coupling a drivetrain of a motor vehicle enginehaving at least one transmission input shaft, in particular for a dualclutch, is provided, having a counter plate for introducing a torquefrom the driveshaft, a clutch plate for channeling the torque to thetransmission input shaft, the clutch plate having a first lining ringfor frictionally engaged torque transfer and a second lining ring whichis movable axially relative to the first lining ring for frictionallyengaged torque transfer, a separator plate which is movable axiallyrelative to the counter plate, the separator plate being positionedbetween the first lining ring and the second lining ring in the axialdirection, and a contact plate which is movable axially relative to thecounter plate by an actuating element to frictionally compress theclutch plate, the first lining ring being positioned between the contactplate and the separator plate in the axial direction and the secondlining ring being positioned between the separator plate and the counterplate, there being n separator plates and n+1 lining rings provided, themovement of the separator plate in the axial direction being coupledwith the movement of the contact plate in the axial direction by meansof a coupling mechanism, where over at least part of the distancebetween an open position of the contact plate corresponding to thedisengaged position of the multi-plate clutch and a maximum closedposition of the contact plate corresponding to the engaged position ofthe multi-plate clutch when the lining rings are worn, a currentdistance translation ratio i(s_(A)) of the axial displacement of thecontact plate to the axial displacement of the separator plate which isfurthest distant in the axial direction from the contact plate at anaxial position s_(A) of the contact plate deviates from i(s_(A))=n+1,and/or a current distance translation ratio i(s_(A))_(j) of the axialdisplacement of the contact plate to the axial displacement of a jthseparator plate at an axial position s_(A) of the contact plate deviatesfrom i(s_(A))_(j)=(n+1)/j where j is counted starting from the counterplate in the direction of the contact plate.

Because of the deviation of the distance translation ratio of thecoupling mechanism from n+1, it is possible, for example, in the case ofa dual-plate clutch where n=1 that the axial travel of the separatorplate is not, or not always, half as great as the travel of the contactplate. As a result, the design demands on the clutch plate and/or on themode of operation of the multi-plate clutch may be reduced. Inparticular, it is possible to provide different axial extensions,different axial air masses and/or different axial compressibilities forthe different lining rings of the clutch plate, and at the same time toensure that the frictional grip of the lining rings begins essentiallysimultaneously. Additionally or alternatively, an intentionallytime-differentiated beginning of the frictional grip of the lining ringsmay be provided, so that for example with the help of the lining ringhaving the first frictional engagement there can already be a firstadjustment of rotational speed in slipping mode, until torque can alsobe transmitted via a lining ring which produces friction subsequently, asmaller rotational speed difference being in effect at the lining ringwhich comes into frictional contact subsequently. The engaging of themulti-plate clutch can occur especially gently because of thesuccessively occurring effectiveness of the lining rings, while becauseof the correspondingly high number of frictional pairings achieved bythe lining rings an especially high maximum torque can be transmitted.At the same time, the lining rings may be adapted in particular to theirdiffering utilization, for example by the lining ring which first entersinto frictional contact being especially strongly sprung radially and/orhaving an especially thick friction lining. Because the distancetranslation ratio of the coupling mechanism deviates from n+1, themulti-plate clutch can easily be adapted to differently dimensionedlining rings, so that transmission of an especially high torque isenabled with the help of a friction clutch with different configurationsof a motor vehicle drivetrain.

For the distance translation ratio of the jth separator plate countingfrom the counter plate in a multi-plate clutch having more than oneseparator plate, a distance translation ratio which differs fromi(s_(A))_(j)=(n+1)/j may be applicable. In a dual-plate clutch, thedistance translation ratio of the single separator plate (n=1) maydiffer from 2:1. In a multi-plate clutch having n=2 separator plates,the distance translation ratio of the separator plate (j=1) assigned tothe counter plate may differ from 3:1, while the distance translationratio of the separator plate (j=2) assigned to the contact plate maydiffer from 3:2. In a multi-plate clutch having n=3 separator plates,the distance translation ratio of the separator plate (j=1) assigned tothe counter plate may differ from 4:1, while the distance translationratio of the subsequent separator plate in the axial direction (j=2) maydiffer from 4:2 and the distance translation ratio of the nextsubsequent separator plate in the axial direction (j=3) may differ from4:3, and so forth. A distance translation ratio i(s_(A)) without theindex j relates to the separator plate located closest axially to thecounter plate, between which separator plate and the counter plate onlyone liner ring is provided. The axial position s_(A) of the contactplate is measured beginning from the open position in which the contactplate is unmoved when the multi-plate clutch is completely disengaged.If no actuating force is exerted on the contact plate by the actuatingelement, the contact plate can be in the open position, so that themulti-plate clutch is designed as “normally open,” or in a closedposition, so that the multi-plate clutch is designed as “normallyclosed.” The actuating element may be designed, for example, as anactuating pot which is essentially rigid in the axial direction, or as alever spring which is elastically yielding in the axial direction. Theactuating element designed as a lever spring may in particular beswivel-mounted on a clutch cover which is connected non-rotatingly tothe counter plate. The actuating element is preferably designed in thenature of a diaphragm spring, and has in particular a diaphragm springbody running in the circumferential direction to provide a diaphragmspring property, while spring tongues may protrude radially inward fromthe diaphragm spring body which may be acted on in the axial directionin particular by a hydraulic actuating system to introduce the actuatingforce.

The coupling mechanism by means of which the motion of the separatorplate is coupled with the contact plate may be based on a leverprinciple, in which the motion of the separator plate is tied to themotion of the contact plate through the currently set lever ratio. Theseparator plate may be firmly connected to the contact plate through thecoupling mechanism, so that the pressure plate can be both pushed andpulled by the contact plate. In particular, the contact plate may pushthe separator plate in the axial direction against the spring force of aspring element when the multi-plate clutch is engaged, whereas when themulti-plate clutch is disengaged the separator plate can follow themotion of the contact plate as a result of the spring force acting onit. Preferably a first return spring connected to the contact plate,particularly in the form of a leaf spring, is provided to move thecontact plate to a defined starting position, especially disengaged. Thedistance translation ratio i(s_(A)) set by the coupling mechanism may beconstant, independent of the axial position s_(A) of the contact plate,or preferably may assume different values depending on the current axialposition s_(A) of the contact plate.

The multi-plate clutch is in particular part of a dual clutch, with thetwo friction clutches of the dual clutch being designed in particular asa dual-plate clutch. The counter plates of the two friction clutches ofthe dual clutch are preferably formed by a common central plate, so thatthe axial space requirement of the dual clutch can be reduced and/orrequisite construction space for the multi-plate clutch(es) can becreated. Furthermore, a second return spring connected to the separatorplate, particularly in the form of a leaf spring, is preferably providedto move the separator plate to a defined starting position, especiallydisengaged. The first return spring and the second return spring are inparticular preferably connected to the counter plate, at leastindirectly, by means of a clutch cover which is firmly connected to thecounter plate. This solves two problems in particular. First, despitethe additional disks and additional plates of the multi-plate clutches,the structure of the dual clutch is not too long axially for the usualdual clutch construction spaces. Second, even without oil lubrication,the plates (contact plates and separator plates) can guarantee clearingof all disks, and thus a disengaging of the clutch that is free of dragtorque. To this end, the invention may provide a guidance mechanismbased on leaf springs for the separator plates. The operating principlecan be based on the operating principle described in DE 100 13 857 A1,DE 10 2011 018 589 A1 and DE 10 2011 086 929 A1, whose content isreferenced here as part of the invention, with various concepts beingcreated by the modification according to the invention, with which therequirements of dry-running dual clutches can be fulfilled.

The contact plate and/or the separator plate can be connected to thecounter plate non-rotatingly but axially movably, in particular totransfer torque. To this end, the contact plate and/or the separatorplate may preferably be guided axially on a clutch cover which is firmlyconnected to the counter plate. The respective lining ring may have inparticular a fastening strip running in the radial direction, which maybe tied to the clutch plate non-rotatingly and relatively movablyaxially if necessary. In particular, at least one friction lining isprovided on each of the two sides of the fastening strip. The respectivefriction lining may be connected to the fastening strip through liningspringing which yields in the axial direction, with the fastening stripitself forming the lining springing. To this end, the fastening stripmay have a wave-like cross section, viewed in the circumferentialdirection.

In particular, the value of the current distance translation ratioi(s_(A)), at least in a segment between the open position of the contactplate and the maximum closed position of the contact plate, inparticular at least in a segment between the open position of thecontact plate and a closed position of the contact plate thatcorresponds to the engaged position of the multi-plate clutch withunworn lining rings, is 0.00<|i(s_(A))−(n+1)|/(n+1)≦5.0, in particular0.01≦|i(s_(A))−(n+1)|/(n+1)≦2.5, preferably0.05≦|i(s_(A))−(n+1)|/(n+1)≦1.5, more preferably0.07≦|i(s_(A))−(n+1)|/(n+1)≦1.0 and by particular preference0.10≦|i(s_(A))−(n+1)|/(n+1)≦0.8. With such a deviation of the distancetranslation ratio from n+1, it is possible to account for a large numberof requirement profiles of the drivetrain and/or of the engineeringdesign of the clutch plate of the multi-plate clutch which are relevantin practice.

The current distance translation ratio i(s_(A)) between the openposition of the contact plate and the maximum closed position of thecontact plate, in particular between the open position of the contactplate and a closed position of the contact plate corresponding to theengaged position of the multi-plate clutch with unworn lining rings,preferably changes at least once; in particular, the current distanceratio i(s_(A)) changes continuously. This makes it possible, inparticular, to react automatically to wearing of friction linings of thelining rings. For example, a first distance translation ratio may beprovided between the open position of the contact plate and a closedposition of the contact plate with unworn linings in new condition,while a second distance translation ratio which differs from the firstdistance translation ratio may be provided between the closed positionof the contact plate with unworn friction linings and the maximum closedposition of the contact plate at the end of the wear range of thefriction linings. This makes it possible to give optimal considerationto the wear which occurs on the friction linings in the repositioning ofthe contact plate and the separator plate coordinated with each other bythe coupling mechanism, for an especially comfortable engagement of themulti-plate friction clutch. In addition, it is possible through thestepwise and/or stepless change of the current distance translationratio, to account for a large number of requirement profiles of thedrivetrain and/or of the engineering design of the clutch plate of themulti-plate clutch which are relevant in practice.

By particular preference, the first lining ring has a first liningspringing and the second lining ring a second lining springing, thefirst lining springing being compressible maximally in the axialdirection by a first axial distance s_(BF1) and the second liningspringing being compressible maximally in the axial direction by asecond axial distance s_(BF2) which differs from the first axialdistance s_(BF1), where in particular0.00<2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦2.0, preferably0.05≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.7, more preferably0.10≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.5 and by particularpreference 0.20≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.0. Due to thedistance translation ratio differing from n+1, it is not necessary todemand the same lining springing for the lining rings used. As a result,it is possible, through conscious use of sufficiently differently actinglining resiliencies, to provide an individually adjusted closingcharacteristic for the multi-plate clutch whereby additional comfortimprovements when engaging the multi-plate clutch can be realized.

In particular, when the contact plate moves from the open position to aclosed position of the contact plate corresponding to the engagedposition of the multi-plate clutch with unworn lining rings, the firstlining ring and the second lining ring are frictionally compressible atdifferent points in time and/or the compressing begins and/or ends atdifferent points in time. Due to the intentionally time-differentiatedbeginning of the frictional grip of the lining rings it is possible forexample with the help of the lining ring having the first frictionalengagement for there to already be a first adjustment of rotationalspeed in slipping mode, until torque can also be transmitted via alining ring which produces friction subsequently, a smaller rotationalspeed difference being in effect at the lining ring which comes intofrictional contact subsequently. The engaging of the multi-plate clutchcan occur especially gently because of the successively occurringeffectiveness of the lining rings, while because of the correspondinglyhigh number of frictional pairings achieved by the lining rings anespecially high maximum torque can be transmitted.

Preferably the first lining ring has a first friction lining with aneffective axial first friction lining thickness d₁, and the secondlining ring has a second friction lining with an effective second axialfriction lining thickness d₂ which differs from the first frictionlining thickness d₁, where in particular 00<2|d₁−d₂|/(d₁+d₂)<2.0,preferably 0.01≦2|d₁−d₂|/(d₁+d₂)≦1.8, more preferably0.05≦2|d₁−d₂|/(d₁+d₂)≦1.5 and by particular preference0.10≦2|d₁−d₂|/(d₁+d₂)≦1.0. This makes it possible in particular toaddress the issue of different friction loads acting on the liningrings, for example if the lining rings are frictionally compressed atdifferent times relative to one another. The different friction liningthicknesses are dimensioned in particular in such a way that under theexpected friction load on the friction linings set by the couplingmechanism the end of the wear range of the friction linings is reachedessentially simultaneously.

By particular preference, it is provided that to form the couplingmechanism the contact plate is connected to the counter plate by meansof a first leaf spring, the separator plate is connected to the counterplate by means of a second leaf spring, and the separator plate issupported on the contact plate by means of a contact pin which restsagainst the first leaf spring or the second leaf spring or some otherelement which forms a contact point. If the contact pin is connected tothe separator plate, the contact pin is supported on the first leafspring. With kinematic inversion, if the contact pin is connected to thecontact plate, the contact pin is supported on the second leaf spring.To this end, the second leaf spring may be lengthened beyond theconnecting point between the second leaf spring and the separator plate,so that the contact pin is not supported on the second leaf springbetween the connecting points of the second leaf spring, but rather thecontact pin which is connected to the contact plate can be supported onthe second leaf spring even outside of this area beyond the point ofconnection to the separator plate. The refinements explained below tothe simplified depiction on the basis of the first alternative, in whichthe contact pin is supported on the first leaf spring, apply by analogyto the kinematic inversion of the second alternative, in which thecontact pin is supported on the second leaf spring. Furthermore, theexample of a refinement explained on the basis of the contact pinapplies by analogy to the element forming the contact points whichdeviates from the geometry of the contact pin. The first leaf spring inparticular can move the contact plate automatically into a defined,especially an open starting position, in the event of a non-exertedactuating force. The second leaf spring In particular can move theseparator plate automatically into a defined, especially an openstarting position, in the event of a non-exerted actuating force. Theoperating principle of the coupling mechanism may be oriented inparticular on the operating principle described in DE 100 13 857 A1, DE10 2011 018 589 A1 and DE 10 2011 086 929 A1, whose content isreferenced here as part of the invention, where to set the desireddistance translation ratio in particular the contact pin may fitaccordingly between the connecting points of the supporting leaf spring,eccentrically to the extension of the leaf spring. The couplingmechanism can thereby be constructed very compactly, and may usecomponents that have already been provided anyway for some other purposefor the motion coupling of the separator plate to the contact plate.

In particular, the separator plate is supportable by means of at leasttwo contact points on the first leaf spring which are offset relative toone another in the circumferential direction and/or in the radialdirection, to change the current distance translation ratio i(s_(A)),the at least two contact points being in particular part of the samecontact pin. The knowledge is utilized here that when the contact plateis moved in the axial direction the part of the first leaf spring thatis connected to the contact plate is carried with it, while the oppositeconnecting point in the axial direction is fixed. As a result, the firstleaf spring undergoes a proportionate swiveling motion in the axialdirection, so that the angle at which the first leaf spring rests on thecontact pin changes. By means of a corresponding geometric design of thecontact pin and/or the provision of at least one additional contact pin,as the angle position relative to the contact pin changes during theaxial movement of the contact plate in the closing direction, the leafspring can first rest on the first contact point and subsequently on thesecond contact point, whereby the distance translation ratio may bechanged depending on the axial position of the contact plate.

The contact pin preferably has a contact contour, in particularessentially convex, directed toward the first leaf spring, to change thecurrent distance translation ratio i(s_(A)), in particular continuously,at least in a segment of the axial movement of the contact plate.Through the geometric design of the contact contour of the contact pin,in particular to form a plurality of contact points, as the angleposition relative to the contact pin changes during the axial movementof the contact plate in the closing position, the first leaf spring isable to roll on the contact contour, whereby the distance translationratio can be changed, in particular continuously, depending on the axialposition of the contact plate.

By particular preference, the contact pin is connected to the separatorplate and secured against rotation. The contact pin can form ananti-rotation protection with the separator plate, in particular bymeans of a cross section contour which deviates from circular shape. Asa result, the contact pin can be mounted in one relative angle position,preferably in exactly one only. A correct orientation of the at leastone contact point and/or of the contact contour of the contact pinrelative to the first leaf spring can be guaranteed thereby.

In particular, the contact pin is prestressed pliably in the axialdirection with a spring force, and/or the contact pin is provided withan end stop, where the end stop blocks the movement of the contact pinin one axial direction and permits it in the opposite axial direction.If there is too strong an axial force acting on the contact pin, inparticular with the multi-plate clutch in the engaged state, the contactpin can flex away or move away, so that damage to the first leaf spring,for example from a plastic deformation, can be avoided.

Preferably, the contact pin bends the first leaf spring in an axialdirection in the maximum closed position of the contact plate, inparticular in a closed position of the contact plate corresponding tothe engaged position of the multi-plate clutch with unworn lining rings.

The contact pin can bend the first leaf spring thereby, so that anespecially compact design of the multi-plate clutch with a small axialconstruction space requirement is possible. The axial elasticity of thefirst leaf spring can be utilized thereby to save construction space.

By particular preference, the contact pin is riveted to the separatorplate, with a contact point of the contact pin that contacts the firstleaf spring being offset in the radial direction relative to a rivetshank of the contact pin, while in particular the contact point, seen inthe direction of the rivet shank axis, is positioned completely next tothe rivet shank cross section and/or a bearing area used only forassembly appears as an extension of the rivet shank, the bearing areacompletely covering the rivet shank cross section. This enables ariveting tool, for example a riveting punch, to be positionedessentially coaxially to the rivet shank without changing the relativeposition of the contact point by a plastic deformation of the contactpin when riveting. This can guarantee functioning operation of themulti-plate clutch. Alternatively, the contact point may be provided inan axial extension of the rivet shank, in which case positioningsurfaces are provided for positioning the riveting tool, in particulararranged symmetrically relative to one another, so that the rivetingtool is not touching the contact point directly during riveting.

The invention also relates to a dual clutch for coupling a driveshaft ofa motor vehicle engine to a first transmission input shaft and/or asecond transmission input shaft, with a first friction clutch forcoupling the driveshaft to the first transmission input shaft and asecond friction clutch for coupling the driveshaft to the secondtransmission input shaft, where the first friction clutch and the secondfriction clutch are designed as multi-plate clutches, which may bedesigned and refined as described above.

The invention will be explained below by way of example with referenceto the accompanying drawings, on the basis of preferred exemplaryembodiments; the features depicted below can each depict an aspect ofthe invention, both individually and in combination. The figures showthe following:

FIG. 1: a schematic sectional view of a dual clutch,

FIG. 2: a schematic perspective view of part of the dual clutch fromFIG. 1,

FIG. 3: a schematic sectional view of an implementation of a multi-plateclutch of the dual clutch from FIG. 1,

FIG. 4: a schematic sectional view of the multi-plate clutch from FIG. 3in a disengaged position,

FIG. 5: a schematic sectional view of the multi-plate clutch from FIG. 3in a partially engaged position,

FIG. 6: a schematic sectional view of the multi-plate clutch from FIG. 3in an engaged position in unworn condition,

FIG. 7: a schematic sectional view of the multi-plate clutch from FIG. 3in a maximum engaged position in worn condition,

FIG. 8: a schematic sectional view of a first embodiment of amulti-plate clutch according to the invention in a disengaged position,

FIG. 9: a schematic sectional view of the multi-plate clutch from FIG. 8in a partially engaged position,

FIG. 10: a schematic sectional view of the multi-plate clutch from FIG.8 in an engaged position in unworn condition,

FIG. 11: a schematic sectional view of the multi-plate clutch from FIG.8 in a maximum engaged position in worn condition,

FIG. 12: a schematic sectional view of a second embodiment of amulti-plate clutch according to the invention in a disengaged position,

FIG. 13: a schematic sectional view of the multi-plate clutch from FIG.12 in a partially engaged position,

FIG. 14: a schematic sectional view of the multi-plate clutch from FIG.12 in an engaged position in unworn condition,

FIG. 15: a schematic sectional view of the multi-plate clutch from FIG.12 in a maximum engaged position in worn condition,

FIG. 16: a schematic sectional view of a third embodiment of amulti-plate clutch according to the invention in a disengaged position,

FIG. 17: a schematic sectional view of the multi-plate clutch from FIG.16 in a partially engaged position,

FIG. 18: a schematic sectional view of the multi-plate clutch from FIG.16 in an engaged position in unworn condition,

FIG. 19: a schematic sectional view of the multi-plate clutch from FIG.16 in a maximum engaged position in worn condition,

FIG. 20: a schematic sectional detail view of a fourth embodiment of amulti-plate clutch according to the invention,

FIG. 21: a schematic sectional detail view of a fifth embodiment of amulti-plate clutch according to the invention,

FIG. 22a : a schematic perspective detail view of a sixth embodiment ofa multi-plate clutch according to the invention,

FIG. 22b : a schematic sectional detailed view of the multi-plate clutchfrom FIG. 22 a,

FIG. 23: a schematic perspective detail view of a seventh embodiment ofa multi-plate clutch according to the invention, and

FIG. 24: a schematic perspective detail view of an eighth embodiment ofa multi-plate clutch according to the invention.

The dual clutch 10 depicted in FIG. 1 may couple a driveshaft 12 via atorsional vibration damper 14 in the form of a dual-mass flywheel to afirst transmission input shaft 16 and a second transmission input shaft18. To this end, a multi-plate clutch 20 is provided in each case, eachof which has a counter plate 22 coupled to the driveshaft 12 and acontact plate 26 which is movable with the help of an actuating element24 in the form of a rigid actuating pot, where the contact plate 26 canalso compress a separator plate 34 which is positioned between a firstlining ring 28 and a second lining ring 30 of a clutch plate 32, whichis movable axially relative to the first lining ring 28. To this end, anactuating force from a hydraulic actuating system 36 may be introducedinto the actuating element 24, in particular to engage the multi-plateclutch 20. The contact plate 26 is connected via a first leaf spring 38,and the separator plate 34 via a second leaf spring 40, at leastindirectly to the counter plate 22. Connected to the separator plate 34is a contact pin 42 which makes contact with the first leaf spring 38,whereby a coupling mechanism 44 is formed which motion-couples theseparator plate 34 to the contact plate 26 in a defined distancetranslation ratio.

Various concepts are presented below for how the separator plates 34 maybe guided in the contact plate path of the contact plate 26 in thecorrect ratio. The distinctive feature of the coupling mechanisms 44presented here and based on leaf springs 38, 40 is that they can guidethe separator plates 34 precisely in accordance with the requirements,even when there are friction packages of the clutch plate 32 havingdifferent plate and lining variants and/or different removal volumes perlining ring 28, 30. Furthermore, a concept is also proposed whichchanges the distance translation ratio between the contact plate path ofthe contact plate 26 and the separator plate path of the separator plate34 depending on the wear condition of the clutch 20.

The basic structure of the multi-plate dual clutch 10 is visible inFIG. 1. The actuating forces of the clutch actuation system 36 can betransmitted to the contact plates 26 of the sub-clutches 20 by means ofactuating bearings 46 and pressure pots 24. The friction package of therespective sub-clutch 20 is then compacted by the contact force whichthus develops. The friction package contains the contact plate 26, thefirst lining ring 28, the separator plate 34, the second lining ring 30and the axially stationary counter plate 22. The two lining rings 28, 30of a sub-clutch 20 together form a multi-part clutch plate 32, each partof which is connected axially movably but torsionally rigidly to one ofthe transmission input shafts 16, 18. The contact plate 26 and theseparator plate 34 are connected to the clutch 20 so that they areaxially movable but fixed in the radial and tangential directions. Sinceonly the contact plate 26 is actively moved by the actuating system 36,the separator plate 34 moves depending on the contact plate 26. The waythe contact plate movement is distributed over the removal volume of thetwo lining rings 28, 30 (removal volume refers to the increase in thegap dimension between the plates 22, 26, 34 adjacent to the lining rings28, 30 in excess of the clamped plate thickness) depends on the movementof the separator plate 34 which is located between the two lining rings28, 30 of the friction package. The way in which the separator plate 34moves relative to the contact plate 26 thus has great influence on thebehavior of the clutch 20. The correct movement diagram makes itpossible to ensure that both lining rings 28, 30 of the clutch plate 32can clear (disengage) correctly, and when the individual lining rings28, 30 become engaged or are again disengaged during the engaging ordisengaging process. Since the movement of the separator plate 34 isimportant, the separator plate 34 should be guided exactly depending onthe movement of the contact plate. To this end, various embodiments ofthe mechanical coupling mechanism 44 are presented below.

As shown in FIG. 2, the separator plates 34 and the contact plates 26are connected by means of leaf springs 38, 40 with parts that are fixedrelative to the clutch. The leaf springs 38, 40 serve to center theplates 26, 34 and to transmit torque. At the same time, the leaf springs38, 40 are elastic in the axial direction and thus make guided axialmovement of the separator and contact plates 26, 34 possible. Bothplates 26, 34 have a plurality of leaf springs 38, 40 or leaf springassemblies distributed around their circumference. In order tosynchronize the separator plate movement in the correct relationship tothe contact plate movement, the separator plate 34 is supported on oneor more first leaf springs 38 of the contact plate 26.

The basic principle is shown in FIG. 3, in which the threeplates—contact plate 26, separator plate 34 and counter plate 22—aredepicted schematically, between which the two lining rings 28, 30 of theclutch plate 32 are located. The first lining ring 28 has a first liningspringing 50 provided on both sides with a first friction lining 48,while the second lining ring 30 has a second lining springing 54provided on both sides with a second friction lining 52. Both thecontact plate 26 and the separator plate 34 are connected by means oftheir own leaf springs 38, 40 to the counter plate 22, which is fixedrelative to the clutch. Thus, the transmission of force and thecentering occur in each case directly between the movable plate (contactplate 26 or separator plate 34) and the components which are fixedrelative the clutch 20 (represented here by the counter plate 22),without tangential forces and centering effect being transmitted fromone of the movable plates 26, 34 to the other. Since FIG. 3 depicts onlya section of a simplified implementation, in each case only one leafspring 38, 40 is visible, which holds the contact plate 26 and theseparator plate 34. It makes sense, however, to distribute a pluralityof leaf springs 38, 40 around the circumference, in particularuniformly, each of which is connected on one side to the movable plate26, 34 and on the other side to a component which is fixed relative tothe clutch 20. Three positions distributed around the circumference haveproven especially effective for the arrangement of the leaf springs 38,40. It is also possible for multiple leaf springs 38, 40 to bepositioned (stacked) on top of another. If the second leaf springs 40,which hold the separator plate 34, also always apply force to it in thedirection of the contact plate 26 and thus in the disengagementdirection of the clutch 20, simple contact points 56 are adequate toguide the separator plate 34. The contact points 56 do not lift off ofthe first leaf springs 38 when the clutch is disengaged 20 because ofthe axial force of the second leaf springs 40. Only when the clutch 20is completely or partially engaged can the contact lift off, when thelining resiliencies 50, 54 of the two lining rings 28, 30 push theseparator plate 34 into a different position than is provided for atthis moment with the help of the leaf springs 38, 40 through thegeometric distance coupling of the coupling mechanism 44.

To ensure that the separator plate 34 takes the correct positionrelative to the contact plate 26 and the counter plate 22, in particularwith the clutch 20 disengaged, a guiding or coupling mechanism 44 forthe separator plate 34 is formed with the help of the leaf springs 38,40. As FIG. 3 shows, the separator plate 34 is supported on one or morefirst leaf springs 38 of the contact plate 26, in order to synchronizethe separator plate movement in the correct ratio with the contact platemovement. Since the first leaf springs 38 are tied on one side to anaxially fixed clutch component and on the other side to the contactplate 26, each leaf spring 38 carries out no axial movement on one sideand on the other side the axial movement of the contact plate 26. Themiddle area of the first leaf spring 38 performs a smaller movement thanthe contact plate 26. How large this movement is depends on thecircumferential position. The closer the approach to the connectingpoint on the contact plate 26, the greater the axial travel becomes. Andleaf spring areas that are in the vicinity of the axially fixedconnecting point perform almost no axial movement. Thus, therelationship of contact plate movement and separator plate movement canbe established by choosing the right support position with the help ofthe contact pin 42. If the support point on the circumference of theclutch 20 is pushed in the direction of the contact plate attachment,the separator plate travel increases relative to the contact platetravel, and if the support point is shifted in the other direction, inthe direction of the fixed connecting point, the separator plate travelis reduced. The first leaf spring 38 functions similarly to a lever thatis used for distance translation. This coupling mechanism 44 of the twomovable plates 26, 34 ensures that when the clutch 20 disengages, bothlining rings 28, 30 of a clutch plate 32 really are relieved anddisengaged, and not for example that one lining ring 28, 30 is clearedtoo far and the other lining ring 30, 28 in exchange too little.

The exact function of the separator plate guidance with the help of thecoupling mechanism 44 will now be described on the basis of thesubsequent figures. A basic layout diagram will be used for this, whichshows the three plates—counter plate 22, separator plate 34 and contactplate 26—and the two lining rings 28, 30. These parts depicted in thelower area of the basic layout diagram correspond to a radial sectionthrough the clutch 20. Also shown is a first leaf spring assembly havinga plurality of first leaf springs 38, which connects the contact plate26 to the counter plate 22 and on which the separator plate 34 may besupported. This upper area of the basic layout diagram corresponds tothe tangential course of the arrangement of the first leaf springs 38 inthe clutch 20. To be able to better depict the movement of the movableplates 26, 34, in the figure, the contact plate 26 and the separatorplate 34 are also each supplied with imagined pointers 58, 60 whichindicate the movement or position change of the plates 26, 34 on animagined fixed scale 62.

The first FIGS. 4 through 7 show the coupling mechanism 44 in the formof a leaf spring guide in a clutch 20 having two equivalentlyconstructed lining rings 28, 30, in which the lining springing 50, 54,the necessary clearing distance and the lining wear which occurs overthe life of the clutch are exactly the same. An especially preferredembodiment of the invention will not be explained until subsequently,when the solutions for the unlike lining rings 28, 30 are presented.However, for an easier start, and as a starting basis for the variantswhich are more difficult to understand, the coupling mechanism 44 forlike lining rings 28, 30 will nevertheless be described here.

FIG. 4 shows the leaf spring guide with the clutch 20 disengaged, withthe contact plate 26 in an open position. Both lining rings 28, 30 arecompletely load-free, so that the lining springing 50, 54 has assumedits greatest thickness. In addition, the clutch 20 is disengaged, sothat both between the counter plate 22 and the separator plate 34 andbetween the separator plate 34 and the contact plate 26 there is agreater interval than the unclamped thickness of the lining rings 28,30, and thus another gap exists between the lining rings 28, 30 andtheir neighbor components 22, 34, 26, at least on one side of eachlining ring 28, 30. Since the focus here is on a leaf spring guide ofthe coupling mechanism 44 for like lining rings 28, 30, the separatorplate 34 is supported exactly in the middle of the free area of thefirst leaf spring assembly 38, which is not supported by its neighborcomponents 22, 26. In this embodiment, the contact point 56 is realizedby a contact pin 42 in the form of a rivet with a round-topped head.

FIG. 5 shows the leaf spring guide 44 with the contact plate 26 movedslightly inward. Since the separator plate 34 is supported exactly inthe middle of the leaf spring assembly 38, in principle the separatorplate travel is essentially exactly half as great as the contact platetravel. This is also indicated by the two pointers 58, 60 on the scale62. This reduces the interval between the counter plate 22 and theseparator plate 34 by the same measure as the interval between theseparator plate 34 and the contact plate 26. In the depicted example,this has now led to the result that for both lining rings 28, 30 theseparation distance has disappeared and the lining rings 28, 30 are nowin contact with their neighbor components 22, 34, 26 on both sides.

In FIG. 6, the clutch 20 has been engaged still further, so that thelining springing 50, 54 of both lining rings 28, 30 has also beencompressed. As soon as the lining springings 50, 54 of the two liningrings 28, 30 are compressed, their forces also act in the axialdirection on the separator plates 34, and not only the forces of theleaf springs 38, 40 and of the coupling mechanism 44. With like liningrings 28, 30 having the same lining springing 50, 54, the separatorplate 34 is always in axial force equilibrium when the lining springing50, 54 of the two lining rings 28, 30 is compressed the same distance.This is the case when the separator plate 34 is always moved half as faras the contact plate 26, whereby in this example the force equilibriumof the lining springing 50, 54 always wants to place the separator plate34 in the same position as the leaf spring guide 44. Both mechanisms,leaf spring guide 44 and force equilibrium therefore work togetherwithout any problems. This is also true in the case of advancing liningwear, as long as it occurs with equal severity on both lining rings(FIG. 7).

A preferred embodiment of the invention is depicted in FIGS. 8 through11, in which a leaf spring guide 44 for a clutch 20 having differentlining rings 28, 30 is depicted. To this end, by way of example, thesecond lining ring 30 between the counter plate 22 and the separatorplate 34 is equipped with none or only very little second liningspringing 54. The first lining ring 28 between the separator plate 34and the contact plate 26 on the other hand has a long first liningspringing 50. Because of the different lengths of lining springing 50,54, the lining rings 28, 30 now also require different removal volumes,so that both can be cleared sufficiently far but not farther thannecessary. The separator plate 34 therefore now no longer travels halfthe distance of the contact plate 26, but is guided by the couplingmechanism 44 so that it travels less than half of the contact platedistance. The separator plate 34 therefore continues to be supported onthe free leaf spring area between the two leaf spring linking points,but the support point is positioned so that its distance from theaxially immovable attachment point of the first leaf spring 38 to thecounter plate 22 is significantly shorter than the distance to themovable connection point of the first leaf spring 38 with the contactplate 26.

When different lining rings 28, 30 are used in a clutch 20, frequentlynot only the lengths of the lining springing 50, 54 and/or the removalvolumes and/or disengagement distances are different, but the ratiosbetween the lining springing lengths and the disengagement distance mayalso be different. If this ratio is not the same, with the couplingmechanism 44 shown in this exemplary embodiment, which guarantees aconstant (or approximately constant) distance translation ratio betweenthe movable plates 26, 34, it is not possible to guarantee asimultaneous start of the torque build-up at both lining rings 28, 30without having to accept an unwanted tensioning of the clutch mechanism44 when the clutch is completely engaged. FIG. 9 shows therefore thatwith this exemplary embodiment, when the clutch 20 is slightly engaged,the first lining ring 28 with the long first lining springing 50 firsttouches its two neighbor components 26, 34, and the second lining ring30 with the shorter second lining springing 54 is not yet clamped. Thisdiffering torque build-up is accepted intentionally with this exemplaryembodiment, so that when the clutch 20 is completely engaged, thecoupling mechanism 44 orients the separator plate so that the contactpoint 56 rests against the first leaf spring 38 with (almost) no force.To that end the coupling mechanism 44 must place the separator plate 34exactly in the position of axial force equilibrium of the two liningspringings 50, 54 and the two separator plate leaf spring forces (FIG.10). The distance translation of the coupling mechanism 44 can naturallyalso only be coordinated with the clearing distances of the two liningrings 28, 30 without allowing for the different lining springinglengths, so that the buildup of torque begins simultaneously at bothlining rings 28, 30. But then the coupling mechanism 44 no longerbecomes force-free when the clutch 20 is completely engaged, but istensioned by the lining springings 50, 54, which want to push theseparator plate 34 into a different position than the coupling mechanism44. This can be accepted if the coupling mechanism 44 tolerates this(for example through first leaf springs 38 matched thereto as in FIG. 19or by a pre-tensioned contact pin 42 as in FIG. 21).

The distances which the contact plate 26 and the separator plate 34travel also change during operation of the clutch 20, since the frictionlining 48, 52 of the lining rings 28, 30 wears. The lining wear on thetwo lining rings 28, 30 of a clutch plate 32 occurs uniformly in mostcases, so that both lining rings 28, 30 become thinner by about the sameamount over time. The contact plate 26 must therefore be moved fartherand farther inward in order to compress the friction package completely.But since the coupling mechanism 44 of this exemplary embodiment alwayswants to move the separator plate 34 less than half the distance of thecontact plate, the coupling mechanism 44 does not guide the separatorplate 34 far enough to bring the separator plate 34 actively into theequilibrium position of the lining springings 50, 54 and the leaf springforces with the same lining wear. The result is that the contact points56 connected to the separator plate 34 lift off of the first leafsprings 38 (FIG. 11).

As the description of the exemplary embodiment depicted in FIGS. 8through 11 shows, with a constant distance translation of the couplingmechanism 44 it is not possible to react individually to boundaryconditions which change the distance relationships between the twolining rings 28, 30. Remedy is provided by a coupling mechanism 44having changeable distance translation. This translation change can beachieved, for example, by two contact points 56, 64 per contact pin 42between the separator plate 34 and the first leaf springs 38. Startingfrom a certain engagement travel, the first leaf spring 38, because ofits changed inclination, rests on the formerly non-bearing secondcontact point 64, and in exchange releases the first contact point 56,which had been in contact until then. Since the two contact points 56,64 are offset around the circumference of the clutch 20 and thus are ata different distance from the axially fixed and the axially movabletie-in of the first leaf spring 38, the distance translation of thecoupling mechanism 44 changes. The operating principle is illustrated inFIGS. 12 through 15. The basic layout diagrams of FIGS. 12 through 14differ from the embodiment depicted in FIGS. 8 through 10 only by thesecond contact point 64 of the contact pin 42. The lining rings 28, 30,the contact plate paths, the separator plate path and the behavior ofthe clutch 20 are exactly as described before. Only when the frictionlinings 48, 52 are worn does the second contact point 64 come to bear.And since the change of the contact points 56, 64, and thus the changeof the distance translation is distance-dependent, depending on theaxial position of the contact plate 26, a clutch 20 with little wearwill also travel only a small distance with the second distancetranslation stage, and a severely worn clutch 20 a large distance. Thismakes it possible to tune the ratio from the distances that theseparator plate 34 travels with the first distance translation ratio andthe second distance translation ratio so that it always corresponds tothe ratio from removal volume in new condition and the increase inremoval volume due to wear. Hence, it is possible that both with a newclutch 20 and with a completely worn clutch 20 the coupling mechanism 44is always force-free, or at least almost force-free, when the clutch 20is fully engaged and fully closed for maximum transmission of torque.

The translation change of the distance translation can be achieved notonly by two contact areas 56, 64 spaced apart, but also by a continuouscontact contour 66, on which the first leaf spring 38 rests at adifferent location, depending on its angular position. It is possiblethen through the form of the contact pin 42 to determine not only thelargest and smallest distance translation of the coupling mechanism 44,but also the course of the translation change. A continuous contactcontour 66 therefore provides for a continuous translation change, inwhich all intermediate values of the distance translation occur. Whenand how rapidly the distance translation changes can be controlled bythe three-dimensional form of the contact contour 66. To achieve acontinuous translation change with flat first leaf springs 38, convexcontact contours 66 in particular are employed. Alternatively, thecontact pin 42 may also be designed with more than two contact points56, 64, so that also more than two translation steps are produced. Witha coupling mechanism 44 having multiple translation steps or acontinuous translation change, at the beginning of the engaging process,for example, the coupling mechanism 44 may provide a translation ratiowhich is matched to the clearing distances of the two lining rings 28,30. Next, the translation ratio may change, so that it is optimallytuned for the lining springing distances, and then the couplingmechanism 44 can adjust to the anticipated lining wear with a newtranslation change.

As described for the previous exemplary embodiments, it is possible thatthe torque build-up does not begin simultaneously in the two liningrings 28, 30 of a sub-clutch 20. Since the number of effective frictionsurfaces decides how much torque can be transmitted at a certain contactforce, the clutch properties can be influenced greatly by thesimultaneous or staggered torque build-up. Depending on the demands onthe clutch 20, a simultaneous or staggered start of the torquetransmission may make sense. How the torque build-up takes place can bedetermined by the distance translation of the coupling mechanism 44and/or the removal volume length. So, FIG. 5, for example, shows asimultaneous start of torque, and FIGS. 9 and 13 show examples in whichthe first lining ring 28 on the contact plate side is the first to comeinto contact. Another exemplary embodiment, in which the second liningring 30, which fits against the counter plate 22, is the first to comeinto contact, is shown in FIGS. 16 through 19. To make it clear that thedifferent torque build-up occurs not only with different lining rings28, 30, two like lining rings 28, 30 are used in the basic layoutdiagrams, whereas preferably differently shaped lining rings 28, 30 areused.

So that the second lining ring 30 is the first to make contact with thecounter plate 22, on the one hand it is less strongly cleared than theother first lining ring 28 on the contact plate 26, and on the otherhand the distance translation of the coupling mechanism 44 is tuned sothat the separator plate 34 travels more than half the contact platedistance (FIGS. 16 and 17). The two measures, which are combined here,can also lead to the desired result individually. If the clutch 20 isengaged further after the start of torque transmission caused by thesecond lining ring 30 in contact with the counter plate 22, because ofthe lining springing force building up on one side, the separator plate34 does not travel as far as it theoretically should because of thedistance translation ratio of the coupling mechanism 44. This increasesthe force at the contact points 56 between the separator plate 34 andthe first leaf springs 38, and the components—in particular the firstleaf springs 38—are bent elastically (FIG. 18). If the first leafsprings are designed for this additional bending load, longer engagementdistances can be realized, such as occur for example due to lining wear(FIG. 19). Alternatively, the elastic deformation may also bedistributed over additional spring elements 68. FIG. 21 shows for this,for example, a contact pin 42 pre-tensioned in the separator plate 34with the help of the spring element 68, for example in the form of adiaphragm spring. If the contact force exerted by the contact pin 42 onthe first leaf springs 38 exceeds the force of the pre-tensioned springelement 68, then the contact pin 42 is shifted relative to the separatorplate 34 and thereby reduces the bending of the first leaf springs 38.

In the coupling mechanisms 44 described here, the first leaf springs 38,which hold the contact plate 26, fulfill three basic tasks. They holdand center the contact plate 26, they always press the contact plate 26in the disengagement direction, and they serve as a translation leverfor the coupling mechanism 44 of the separator plate 34. These tasks mayalso be distributed among various components. The coupling mechanism 44,as it is presented here, has a translation element which is connected onone side to a component which is fixed axially relative to the clutch 20and on the other side is moved along with the contact plate movement, sothat between the two outer tie-in points the correct axial distance forthe separator plate 34 can be measured out. Whether this couplingelement is a leaf spring 38 or a lever-like element of some other designis not crucial for the operating principle of the coupling mechanism 44.One or more leaf springs 38, 40 may be utilized as a translationelement, even if they do not fulfill the other clutch-relevant functionspreviously enumerated. Furthermore, the contact pin 42 or some othercoupling element may be connected to the contact plate 26 and besupported on the second leaf spring 40, which is connected to theseparator plate 34. Furthermore, in comparison to the clutch 20 designedby way of example on the basis of a dual-plate clutch, more than oneseparator plate 34 may be provided, which may be coupled with thecontact plate 26 accordingly by means of one of the coupling mechanisms44 described above.

In the contact points 56, 64 between the separator plates 34 and thefirst leaf springs 38, which fix the contact plates 26, what isimportant basically is not the design but only the contact, so that thefirst leaf springs 38 can move the separator plate 34 in the axialdirection. Nevertheless, there are naturally certain solutions which areespecially appropriate technically, such as the variants presentedbelow.

FIG. 20 shows the contact pin 42, which has already been designedrepeatedly in the previous figures as a support rivet. The rivet 42 canbe connected easily to very different separator plates 34 and separatorplate materials. In addition, the rivet 42 can very easily be hardened,coated, or made of an especially hard or lubricious material. Thisenables the contact point 56 to be made robust and subject to littlewear, and can reduce the hysteresis due to friction. The exemplaryembodiment shows a rivet with two contact points 56, 64. Both the centerelevation and the edge of the rivet head may be utilized as contactpoints 56, 64. Either one or both contact points 56, 64 may be realizedand used. A rivet 42 having two contact points 56, 64 is especiallyattractive for coupling mechanisms 44 having changeable translation,since this eliminates the need of placing two individual rivets 42side-by-side. In addition, a continuous transition contour 66 betweenthe two contact points 56, 64 spaced at a maximum interval can alsoenable and influence a continuous translation change of the distancetranslation.

Instead of rotationally symmetrical rivets, the contact pins 42 may alsobe designed as shaped rivets, which offer the first leaf spring 38 alarger supporting surface and can make linear contact possible. If therivet 42 is no longer rotationally symmetrical, it should be connectedto the separator plate 34 in the correct orientation to achieve thecorrect separator plate position and the desired distance translation.FIGS. 22a and 22b show by way of example the shaped rivet 42 with thetwo contact points 56, 64, which is already known from the exemplaryembodiment with changeable translation (FIGS. 12 through 15). In thedetailed illustrations it can be seen how the shaped rivet 42 can bealigned on an axially protruding bar 72 of the contour of the separatorplate 34 by means of an outer contour 70 of its non-round head. The bar72 of the separator plate 34 simplifies the assembly alignment, andprevents the rivet 42 from unwanted turning, even during operation ofthe clutch.

Two other exemplary embodiments, in which the rivet 42 is aligned by aflattened rivet shank 74, are shown in FIGS. 23 and 24. The rivet headshave an axially protruding contact bar 76 that forms the contact contour66, by which the separator plates 34 can be supported on the first leafsprings 38. The course of the distance translation can be controlled bythe contour 66 of the contact bar 76. A continuous, mostly convexcurvature of the contact bar 76 makes it very simple to elicit acontinuous translation change, which can be adapted in particular to thelining springings 28, 30, the clearing distances and lining wear rates.To prevent damage to the contact bar 76 while the rivet 42 is being set,the riveting die may be braced next to the contact contour 66 which thefirst leaf springs 38 utilize. The supporting surfaces for the rivetingmay be located on both sides of the contact bar 76 (FIG. 23).Alternatively, a single supporting surface for the riveting process mayalso be provided on one side of the contact bar 76 (FIG. 24). It isexpedient in this case not to locate the contact bar 76 directlyextending the axis of the rivet shank 74, so that the supporting surfacecan largely or completely cover the rivet shank 74.

FIG. 21 shows a contact pin 42 which is inserted into an opening 78 inthe separator plate 34 so that it is axially movable. On one side of theseparator plate 34 the pin shaft 80 is provided with a locking ring 82,which serves as a stop and is braced against the separator plate 34. Onthe other side is the pin head with the contact contour 66. Between thepin head and the separator plate 34 is a pre-tensioned diaphragm spring68, which presses the contact pin 42 against the stop formed by thelocking ring 82. Because of the pre-tensioning force of the diaphragmspring 68, the contact pin 42 acts like a rigid contact point 56 andfulfills all characteristics described previously for the contact points56, 64, as long as the contact force does not exceed the pre-tensioningforce of the diaphragm spring 68. If this is the case, the contact pin42 is shifted relative to the separator plate 34. This can limit themaximum axial forces exerted on the separator plate 34 by the couplingmechanism 44, and/or change distance ratios depending on the force.

Leaf springs 38, 40 are mainly used in dry dual clutches 10, because oftheir low friction. All concepts presented here may also be employed inwet-running clutches, however.

REFERENCE LABELS

-   10 dual clutch-   12 drive shaft-   14 torsional vibration damper-   16 first transmission input shaft-   18 second transmission input shaft-   20 multi-plate clutch-   22 counter plate-   24 actuating element-   26 contact plate-   28 first lining ring-   30 second lining ring-   32 clutch plate-   34 separator plate-   36 actuating system-   38 first leaf spring-   40 second leaf spring-   42 contact pin-   44 coupling mechanism-   46 actuating bearing-   48 first friction lining-   50 first lining springing-   52 second friction lining-   54 second lining springing-   56 contact point-   58 first pointer-   60 second pointer-   62 scale-   64 second contact point-   66 contact contour-   68 spring element-   70 outside contour-   72 bar-   74 rivet shank-   76 contact bar-   78 opening-   80 pin shaft-   82 locking ring

1. A multi-plate clutch, in particular a dual-plate clutch, for couplinga driveshaft (12) of a motor vehicle engine to at least one transmissioninput shaft (16, 18), in particular for a dual clutch (10), having acounter plate (22) for introducing a torque from the driveshaft (12), aclutch plate (32) for channeling the torque to the transmission inputshaft (16, 18), the clutch plate (32) having a first lining ring (28)for frictionally engaged torque transfer and a second lining ring (30)which is movable axially relative to the first lining ring forfrictionally engaged torque transfer, a separator plate (34) which ismovable axially relative to the counter plate (22), the separator plate(34) being positioned between the first lining ring (28) and the secondlining ring (30) in the axial direction, and a contact plate (26) whichis movable axially relative to the counter plate (22) by an actuatingelement (24) to frictionally compress the clutch plate (32), the firstlining ring (28) being positioned between the contact plate (26) and theseparator plate (34) in the axial direction and the second lining ring(30) being positioned between the separator plate (34) and the counterplate (22), there being n separator plates (34) and n+1 lining rings(28, 30) provided, the movement of the separator plate (34) in the axialdirection being coupled with the movement of the contact plate (26) inthe axial direction by means of a coupling mechanism (44), where over atleast part of the distance between an open position of the contact plate(26) corresponding to the disengaged position of the multi-plate clutch(20) and a maximum closed position of the contact plate (26)corresponding to the engaged position of the multi-plate clutch (20)when the lining rings (28, 30) are worn, a current distance translationratio i(s_(A)) of the axial displacement of the contact plate (26) tothe axial displacement of the separator plate (34) which is furthestdistant in the axial direction from the contact plate (26) at an axialposition s_(A) of the contact plate (26) deviates from i(s_(A))=n+1and/or a current distance translation ratio i(s_(A))_(j) of the axialdisplacement of the contact plate (26) to the axial displacement of ajth separator plate (34) at an axial position s_(A) of the contact plate(26) deviates from i(s_(A))_(j)=(n+1)/j, where j is counted startingfrom the counter plate (22) in the direction of the contact plate (26).2. A multi-plate clutch according to claim 1, characterized in that thevalue of the current distance translation ratio i(s_(A)), at least in asegment between the open position of the contact plate (26) and themaximum closed position of the contact plate (26), in particular atleast in a segment between the open position of the contact plate (26)and a closed position of the contact plate (26) that corresponds to theengaged position of the multi-plate clutch (20) with unworn liningrings, is 0.00<|i(s_(A))−(n+1)|/(n+1)≦5.0, in particular0.01≦|i(s_(A))−(n+1)|/(n+1)≦2.5, preferably0.05≦|i(s_(A))−(n+1)|/(n+1)≦1.5, more preferably0.07≦|i(s_(A))−(n+1)|/(n+1)≦1.0 and by particular preference0.10≦|i(s_(A))−(n+1)|/(n+1)≦0.8.
 3. A multi-plate clutch according toclaim 1 or 2, characterized in that the current distance translationratio i(s_(A)) between the open position of the contact plate (26) andthe maximum closed position of the contact plate (26), in particularbetween the open position of the contact plate (26) and a closedposition of the contact plate (26) corresponding to the engaged positionof the multi-plate clutch (20) with unworn lining rings (28, 30),changes at least once; in particular, the current distance ratioi(s_(A)) changes continuously.
 4. A multi-plate clutch according to oneof claims 1 through 3, characterized in that the first lining ring (28)has a first lining springing (50) and the second lining ring (30) asecond lining springing (54), the first lining springing (50) beingcompressible maximally in the axial direction by a first axial distances_(BF1) and the second lining springing (54) being compressiblemaximally in the axial direction by a second axial distance s_(BF2)which differs from the first axial distance s_(BF1), where in particular0.00<2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦2.0, preferably0.05≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.7, more preferably0.10≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.5 and by particularpreference 0.20≦2|s_(BF1)−s_(BF2)|/(s_(BF1)+s_(BF2))≦1.0.
 5. Amulti-plate clutch according to one of claims 1 through 4, characterizedin that the first lining ring (28) has a first friction lining (48) withan effective axial first friction lining thickness d₁ and the secondlining ring (30) has a second friction lining (52) with an effectivesecond axial friction lining thickness d₂ which differs from the firstfriction lining thickness d₁, where in particular00<2|d₁−d₂|/(d₁+d₂)<2.0, preferably 0.01≦2|d₁−d₂|/(d₁+d₂)≦1.8, morepreferably 0.05≦2|d₁−d₂|/(d₁+d₂)≦1.5 and by particular preference0.10≦2|d₁−d₂|/(d₁+d₂)≦1.0.
 6. A multi-plate clutch according to one ofclaims 1 through 5, characterized in that when the contact plate (26)moves from the open position to a closed position of the contact plate(26) corresponding to the engaged position of the multi-plate clutch(20) with unworn lining rings (28, 30), the first lining ring (28) andthe second lining ring (30) are frictionally compressible at differentpoints in time and/or the compressing begins and/or ends at differentpoints in time.
 7. A multi-plate clutch according to one of claims 1through 6, characterized in that to form the coupling mechanism (44) thecontact plate (26) is connected to the counter plate (22) by means of afirst leaf spring (38), the separator plate (34) is connected to thecounter plate (22) by means of a second leaf spring (40), and theseparator plate (34) is supported on the contact plate (26) by means ofa contact pin (42) which rests against the first leaf spring (38) or thesecond leaf spring (40) or some other element which forms a contactpoint (56, 64).
 8. A multi-plate clutch according to claim 7,characterized in that the separator plate (34) is supportable by meansof at least two contact points (56, 64) on the first leaf spring (38)which are offset relative to one another in the circumferentialdirection and/or in the radial direction, to change the current distancetranslation ratio i(s_(A)), the at least two contact points (56, 64)being in particular part of the same contact pin (42).
 9. A multi-plateclutch according to claim 8, characterized in that the contact pin (42)preferably has a contact contour (66), in particular essentially convex,directed toward the first leaf spring (38), to change the currentdistance translation ratio i(s_(A)), in particular continuously, atleast in a segment of the axial movement of the contact plate (26). 10.A multi-plate clutch according to one of claims 6 through 9,characterized in that the contact pin (42) is connected to the separatorplate (34) and secured against rotation.
 11. A multi-plate clutchaccording to one of claims 6 through 10, characterized in that thecontact pin (42) is prestressed pliably in the axial direction with aspring force, and/or the contact pin (42) is provided with an end stop,where the end stop blocks the movement of the contact pin (42) in oneaxial direction and permits it in the opposite axial direction.
 12. Amulti-plate clutch according to one of claims 6 through 11,characterized in that the contact pin (42) bends the first leaf spring(38) in an axial direction in the maximum closed position of the contactplate (26), in particular in a closed position of the contact plate (26)corresponding to the engaged position of the multi-plate clutch (20)with unworn lining rings (28, 30).
 13. A multi-plate clutch according toone of claims 6 through 12, characterized in that the contact pin (42)is riveted to the separator plate (34), with a contact point (56, 64,66) of the contact pin (42) that contacts the first leaf spring (38)being offset in the radial direction relative to a rivet shank (74) ofthe contact pin (42), while in particular the contact point (56, 64,66), seen in the direction of the rivet shank axis, is positionedcompletely next to the rivet shank cross section, and/or a bearing areaused only for assembly appears as an extension of the rivet shank, thebearing area completely covering the rivet shank cross section.